Most Americans already eat more protein than their bodies need. And eating too much protein can increase health risks. High-protein animal foods are usually also high in saturated fat. Eating large amounts of high-fat foods for a sustained period raises the risk of coronary heart disease, diabetes, stroke and several types of cancer. People who can't use excess protein effectively may be at higher risk of kidney and liver disorders, and osteoporosis.

The most consistent risk factor for colorectal cancer was dietary protein, which was associated with a twofold-to-threefold relative risk for colon cancer and for rectal cancer in women for all levels of consumption above the base line (i.e., the lowest consumption quintile).

Evidence from observational studies supports the generalizability of these clinical trials to the general population. Wrone et al [138] examined the association between dietary protein intake as assessed from 24-hour dietary recall and the prevalence of albuminuria among NHANES III participants. They reported that persons with both hypertension and diabetes and in the highest quintile of dietary protein consumption had over threefold increased risk for albuminuria compared with those in the lowest quintile of protein intake. Protein intake among participants in the Nurses' Health Study measured using a semiquantitative food-frequency questionnaire was associated with the rate of decline in estimated GFR among women with impaired kidney function at baseline [139]. The rate of GFR change over 11 years of follow-up among women with normal renal function and a high protein intake was 0.25 mL/min/1.73 m2 compared with -1.69 mL/min/1.73 m2 per 10-g increase in protein intake among women with an estimated GFR between 55 and 79 mL/min/1.73 m2. Interestingly, the source of dietary protein consumption was related to the rate of decline in GFR among women with impaired kidney function with nondairy animal protein associated with a significantly greater change in estimated GFR [139].

I apologise I don't have time to do this properly, and I don't have journal access at home. But a few PubMed searches turn up plenty of "inconclusives" (i.e. no signs of adverse effects) as well as suggestions of problems.

ETA: from your colon cancer link

Quote:

The increased risk associated with high protein and total energy was confined to those consuming a low fiber diet,

and these guys: (I don't know the validity of this journal unfortunately)

Quote:

Recent trends in weight loss diets have led to a substantial increase in protein intake by individuals. As a result, the safety of habitually consuming dietary protein in excess of recommended intakes has been questioned. In particular, there is concern that high protein intake may promote renal damage by chronically increasing glomerular pressure and hyperfiltration. There is, however, a serious question as to whether there is significant evidence to support this relationship in healthy individuals. In fact, some studies suggest that hyperfiltration, the purported mechanism for renal damage, is a normal adaptative mechanism that occurs in response to several physiological conditions. This paper reviews the available evidence that increased dietary protein intake is a health concern in terms of the potential to initiate or promote renal disease. While protein restriction may be appropriate for treatment of existing kidney disease, we find no significant evidence for a detrimental effect of high protein intakes on kidney function in healthy persons after centuries of a high protein Western diet.

So, while there's lots of suggestions, I don't see any real consensus. (Please don't interpret me as arguing for the sake of it. I'm genuinely interested, and without time to study the literature properly, wondered if you'd seen something conclusive which I hadn't.)

3.) Protein is not some magical substance where the recommended daily allowance is good, more is better, and even more turns you into a superhero. As with fat and sodium, while it's important to get enough, most people in the first world get too much, and that can cause health problems.

My doctor told me that years ago. I think she was more concerned about the fat the usually accompanies protein in a omnivorous diet, but her contention was that the "eat protein whenever you can" thing so common in the West came from a time when protein was little more scarce and a lot more expensive than it is today.

She also told me the bit about where you don't have to get all the amino acids at one sitting.

Yeah, that first point is kinda irrelevant, and besides unless you're getting everything from meal replacement crud, there's carbs and fat in most sources you'll turn to. As to the second- I really don't think there are, until you get to absurdly large amounts. Not real, proven problems anyway, just another of those "can't guarantee against it" deals.

So sorry to have introduced a point you deem irrelevant into the thread.

So sorry to have introduced a point you deem irrelevant into the thread.

Oh now wait a minute. You said too much protein causes health problems, and then made a claim based on under-consuming carbs and fats.
Given that you'd have to be eating some seriously bizarre food combinations for the first to imply the second, that second point is basically irrelevant to your argument.

For protein, my main source is the vegetables I eat. I eat a lot of greens, and beans. I've never eaten quinoa in my life, though I would say that if somebody does eat a lot of it then they possible find it less' unpalatable' than other types of farming, particularly if they're vegetarian or vegan for ethical or ecological reasons. As has been said to me numerous times, you often can't win if you're trying to shop ethically. I doubt it's more an unpalatable truth than exists for many other types of farming industry.

That seems to be the reaction to a lot of choices related to lifestyle, health and environmental concerns:

If you promote healthy eating (and options that help with that, like having reasonably priced produce available, offering proper portion sizes instead of 'bucket' and 'bigger bucket', and posting nutritional information), you'd better not ever think of eating a hamburger again.

If you try to avoid using a car when it's not necessary, you'd better not be seen using a vehicle to bring home a big load of groceries or dare to go on a road trip.

If you choose to follow a vegetarian diet (or make any other food decisions based on ethical reasons), you'd better be completely flawless in all areas of your life and not a single bite you consume can even slightly inconvenience another person or animal.

If you try to grow your own food or buy local, you shouldn't be seen in a grocery store, and you'd better not be caught eating pineapple (my step sister has gotten this one).

If you try to reduce your energy consumption, you'd better not take advantage of modern conveniences again in your life (this is a popular one in the letter to the editor section of my paper. Any time someone brings up possibly trying to slow down environmental damage, the response is along the lines of "hope you enjoy living in a shack in the woods")

Some people seem to resent that other people make decisions that they (the critics) would find inconvenient, more expensive or less pleasant. Because of that, if you're not 100% perfect with it, you're cheating. After all, how can you judge someone (and these types always assume they're being judged) if you're not flawless yourself? For some people, a person choosing to live differently than the norm is only doing it to make a statement, and it's their job to poke holes in that argument so they can show these misguided vegans/health nuts/environmentalists how stupid they are. I think some genuinely think that it's almost a religious belief, and they want to catch people not following the faith.

I mean, obviously it's not enough just to make slightly better decisions in some areas of your life. If you can't be perfect, why bother trying? You have to be all or nothing, or you're a hypocrite.

Oh now wait a minute. You said too much protein causes health problems, and then made a claim based on under-consuming carbs and fats.
Given that you'd have to be eating some seriously bizarre food combinations for the first to imply the second, that second point is basically irrelevant to your argument.

No, I didn't make the original claim that eating too much protein causes health problems. I was simply providing a possible way that what Esprise Me said could have been true. I may be reading your tone wrong but you seem very annoyed.

If you choose to follow a vegetarian diet (or make any other food decisions based on ethical reasons), you'd better be completely flawless in all areas of your life and not a single bite you consume can even slightly inconvenience another person or animal.

It is worth noting that failure to follow this strict abstract, can bring criticism from other vegetarians, or non-vegetarians, alike.

It is worth noting that failure to follow this strict abstract, can bring criticism from other vegetarians, or non-vegetarians, alike.

I guess I've been lucky then, because I don't follow that strict abstract (I think it would be extremely difficult to do so) and I have never been criticized for it. I've never been criticized by other vegetarians for any of my food choices, and the closest thing to criticism I've received from non-vegetarians is the occasional rude comment about something I'm eating ("how can you eat that?", for example).

I agree with Lainie. 31 years a vegetarian, and I've never been criticized by other vegetarians. Meat-eaters can be rude, though. I don't comment on what they're eating; I don't see why it's necessary for them to comment on my food choices.

"Many quinoa-lovers have hit the existential skids recently, thanks to a story in the Guardian about the supposedly negative effects of buying imported quinoa.
...
But the idea that worldwide demand for quinoa is causing undue harm where it's produced is an oversimplification at best. At worst, discouraging demand for quinoa could end up hurting producers rather than helping them..."

Or ask me why I don't eat meat. I don't ask them to explain their food choices; I can't imagine they would take kindly to it.

I honestly think this applies to anyone who eats (or avoids) anything in a not-standard way. Like your steak well done? "You're ruining a perfectly good piece of meat!". Like your steak a little pink in the middle? "You're going to get mad cow disease!" Only want ham, black olives and vinegar on your subway sandwich? "But you're paying for all the other veggies too!" You a little over weight? "Ha, that salad ain't going to help!" You a little over weight and enjoying a treat? "Ha, no wonder you're fat!" Need to gain some weight to be healthy? "I wish I could eat [whatever] and still be thin like you!" Avoiding foods for religious reasons? "How could you ever live without [whatever]!" Heck, with its insane popularity as of late, I've heard "I can't believe you don't like bacon!" gasped at people who were totally fine eating other pork products.

Unfortunately, vegetarians fall outside the "normal, comfortable, average eating pattern", which means they - any anyone else who dares to be different - get commented on. It's not that those who forgo meat are being singled out - it's that they're lumped into the same group as the other "different" people who get pestered about what they are or are not eating.

Somebody said to me the other day, "I dislike that so much, I just can't understand why anyone would like it," and I smiled not-so-sweetly at her and said, "Because they're not you?" and kept eating it.
I don't comment on (g)your food. I don't say, "I hate soup! It's gross! Why are you eating it?" or "Your food smells weird," even if it does. So why do (g)you find it acceptable to say "How can you eat the same thing every day for lunch?" Because I LIKE it, otherwise I wouldn't make it and freeze it every week. I didn't mind the first time, but did (g)you think my answer was going to change? Or are you trying to call attention to the weird girl who eats the same thing every day?
Not that it's like that, people at school are actually talking about all of us going away together next March Break, we're actually friends. But I still see some vestige of schoolyard nastiness about it.

You're probably right; I just see the meat one because it's the one that happens to me. Why do people have to be so rude? If you have to comment on someone's food, why not "That looks good."

On the other hand, I have had vegetarians lecture me when I eat meat. Not you, though. You once allowed bacon to be served on your plate and then gave it to me.

Where I run into it the most, however, is in not drinking coffee. I have finally gotten a French press for the house, but the way some people act not knowing how to brew coffee is an unforgivable act of extreme inhospitality. And I get comments alot about how can I keep awake and have even had it linked to being fat. Very strange.

I have a vegetarian friend who actually cooked my chicken breasts in the same pan as her Shake n' Bake tofu. In fact, my back was killing me so she actually prepared them for me, though I would never have asked that of her.
Actually, the first time she referred to her Shake n' Bake Tofu was on the phone and there was this silence on the line as I contemplated a huge brick of tofu with Shake n' Bake on the outside. But it turns out that she makes fingers out of it and they're quite tasty with plum sauce.
i don't drink coffee. I don't drink tea, either, except for one cup of green tea with lemon that I tolerate daily (if I can) because of the health benefits. As someone who is supposed to limit their caffeine as much as possible it's not good for me. You could always try that reason if people are being rude.